Modular input/output (I/O) systems for industrial automation control systems are well-known and in widespread use. Referring to FIG. 1, a known modular I/O system MIO′ includes a network adapter module AM′ that is operatively connected to an industrial automation network N so that the network adapter module AM′ receives data from, transmits data to, and otherwise communicates with an industrial control module or “controller” C also connected to the network N.
The adapter module AM′ is mounted to a DIN rail D or other support structure. One or more terminal base units TB′ (TB1′,TB2′,TB3′, etc.) are also mounted to the DIN rail D, with a first terminal base unit TB1′ located adjacent and operably physically and electrically connected to the network adapter module AM′ and with the additional terminal base units TB2′,TB3′ operably physically and electrically connected together one after the other in a sequential manner such that a modular backplane circuit for communicating electrical power and data (referred to as a “backplane”) is constructed through the successively connected terminal base units TB′ and operably connects each terminal base unit TB′ to the adapter module AM′ and, thus, to the controller C.
Each terminal base unit TB′ (sometimes referred to simply as a “terminal base”) includes a terminal block BK′ comprising a plurality of cage clamps, spring clamps, screw terminals, or other wiring connectors WC′ that are adapted to be connected to field cables or field wires FW that are each associated with a field device FD that is typically an analog or digital device such as a sensor, switch, probe, thermocouple, RTD, encoder, or the like that is associated with the process or machine being controlled (the controlled system CS) by the controller C. The terminal block BK′ is typically a separate structure that is assembled to the terminal base TB′ but the terminal block BK′ can alternatively be defined as an integral or one-piece part of the terminal base TB′. Different varieties of terminal blocks BX′ can be used depending upon the particular configuration required for the field device wiring connectors WC′, with some having different common terminals, ground connections, voltage supply terminals, and the like.
A respective I/O module M′ is operatively removably connected to each terminal base TB′ such that the installed I/O module M′ communicates with the field device wiring connectors WC′ of the corresponding terminal base TB′ to which the I/O module M′ is physically connected, and the I/O module M′ also communicates with the network adapter module AM′ (and from there to the industrial automation controller C) over the backplane circuit such that input/output data is provided between the controller C and field device(s) FD connected to the corresponding terminal base TB′. Each I/O module M′ is selected and configured to perform one or more specialized input/output functions such as DC input, DC output, AC input, AC output, analog input and/or output, RTD and/or thermocouple input and/or thermocouple output, or the like.
In certain instances, a terminal block BK′ lacks the required number and/or type of wiring connectors WC′ necessary to complete the wiring for one or more associated field devices FD. In such case, using presently known systems, it is necessary for an end user to install a separate auxiliary wiring connector device XD′ as near as possible to the relevant terminal base TB′. In this known arrangement, the auxiliary wiring connector device XD′ is separate and spaced-apart from the terminal block BK′ and is provided with the necessary power, ground, or other auxiliary wiring connections XC′. One or more of the auxiliary wiring connectors XC′ is connected to an auxiliary input or output connection AX such as a ground path, a voltage supply, a conditioning circuit, or the like. The field device wiring or related cabling/wiring must be lengthened and/or otherwise routed to mate with the wiring connections XC′ of the separate auxiliary wiring device XD′ (see field wires FW′) which makes the wiring system more complicated and less efficient. Also, the use of such a separate auxiliary wiring connector device XD′ makes it more difficult for maintenance and service personnel to understand the original wiring pattern and to duplicate same as needed after removal and replacement of a defective terminal base TB′. Accordingly, a need has been identified for an auxiliary wiring device that overcomes these and other deficiencies while providing better overall results.